DOBBS FERRY (WABC) -- Westchester County Police say the victim of an accident on the Saw Mill River Parkway in Dobbs Ferry was drag racing moments before the deadly accident Wednesday.

Police say an on duty officer came across two cars that were indicative of drag racing as the cars were lined up driving very slowly.

An officer who witnessed the cars lining up got around the slow moving cars and up ahead they may have been attempting to slow traffic. The officer saw taillights of two cars speeding ahead.

Police say the officer couldn't catch up and lost sight of their taillights.

The officer was then flagged down by motorist who said a car just went flying off the bridge.

Police say they are still looking for driver of the other car that was possibly involved.

The victim was identified as 21-year-old Christopher Seguinot of West Harrison, who was alone in the 2010 Chevrolet Camaro. He was heading northbound when he drove off the Ashford Avenue Bridge at Exit 17 around 12:30 a.m.

Authorities say the vehicle plunged 20-30 feet and landed under the bridge.

The bridge was closed as investigators examined the scene. The northbound parkway at Lawrence Street also was closed.